1. Field of the Invention
The present invention relates to image-capturing apparatuses, image processing systems, control methods, and storage media storing computer-readable processing steps for implementing the methods, all of which are used for digital cameras connectable through communication means such as a USB to personal computers and to printers.
2. Description of the Related Art
As image-pickup devices such as CCDs have had a large number of pixels, digital cameras can include image-pickup devices having two million pixels to three million pixels these days.
Images taken by such digital cameras (hereinafter called just “digital cameras”) having a large number of pixels can be enjoyed on a screen of a personal computer (hereinafter called a “PC”) or can be put on web sites. There is also a high demand for printing them by means of a printer and enjoying them as printed photographs.
Since images taken by a digital camera are written in a memory built in the digital camera or in a storage medium, such as a non-volatile memory card, detachable from the digital camera, however, it is necessary, for example, that the images written into the storage medium be sent to a PC through communication means, such as a USB or a serial bus (RS-232C), processed for printing by the PC, and printed by a printer, in order to print the images.
Alternatively, when taken images have been written into a non-volatile memory card, it is necessary that the non-volatile memory card be directly connected to a PC, and that the taken images written into the non-volatile memory card be sent to the PC and printed.
The above-described work for printing taken images is very troublesome, very complicated, and time consuming for users, and taken images may be lost due to an erroneous operation.
In addition, when the user wants to print an image stored in a digital camera, at a place where the user is now located, it is impossible to enlarge, print, and enjoy the image without a PC at the place.
To solve the foregoing problems, a digital camera has been proposed, for example, in Japanese Patent Laid-Open No. Hei-11-046331, which has a camera-printing-control function to implement so-called direct printing, which means that taken images are printed without a PC.
More specifically, the digital camera such as that described in Japanese Patent Laid-Open No. Hei-11-046331 has a function for outputting taken-image data from itself to an external apparatus as well as a function (printing function) for printing a desired taken image with a desired printing specification (such as the number of prints, a printing size, and a printing color).
As one of their most important characteristics, digital cameras need to be portable. Therefore, they should be compact and lightweight as the top priority.
Also, it is, of course, always demanded that digital cameras have low prices, have good responses when capturing images, and allow high-speed image capturing.
Due to the structures of the digital cameras, such as that described in Japanese Patent Laid-Open No. Hei-11-046331, they have the following problems (1) to (3) when they have a printing function:
(1) When digital cameras having a large number of pixels have a printing function, a very large amount of taken-image data (printing data) needs to be sent to a printer. Especially when serial communication means such as RS-232C is used for sending the printing data, it takes a very long time to send it.
When a parallel port provided for printers in many cases is used, digital cameras need to have a connector having a large number of pins, making the cameras larger or increasing their price.
(2) To execute printing processing in the digital cameras, it is necessary that the digital cameras have a high-speed CPU.
Because a high-speed CPU generally consumes a large amount of electric power while digital cameras are provided with a battery having a small capacity, however, when a high-speed CPU is provided for digital cameras, the battery is consumed earlier due to high power consumption.
In addition, since digital cameras have a small body, when a high-speed CPU is provided for a digital camera, more heat is generated, the surface temperature of the body rises, and the user feels hot when the user touches the camera body.
(3) To execute printing processing by a CPU in the digital cameras, it is generally required that a taken image to be printed is developed for each ink color. Therefore, the CPU needs a large memory capacity, and the number of memory chips to be mounted on the digital cameras is increased. The manufacturing cost of the digital cameras is thereby increased.